We can send a small object anywhere, but we can't send enough of them everywhere. If an intelligent species directed such an object to our galaxy, how close would is need to be for us to detect it? They physical object alone would be near impossible without it being extremely close, and even if it was producing a signal to be detected there is a limit based on size and how much energy it has on board. Even that would be hard to detect at any sort of galactic distances.
>And yet there are vastly larger motivations for sending a spacecraft than sending a signal.
Unless the signal is directed, it covers an exponentially increasing area, which is also why it has limited range. There is a fundamental trade off between range and area, meaning that there is an upper bounds on the volume we can contact. How likely is life found in that volume?
>Whether anyone would consider that "rare" or not is irrelevant.
When it is part of the question, how is it irrelevant? If it was on the other side of the galaxy, how would they know to send someone to our solar system and how far could we view their spacecraft if they weren't in our solar system? And that still assume a neighbor in the galaxy. If they weren't, the space between galaxies greatly changes the equation.